The successors of Constantine extended still further the boundaries of the principality. After gaining possession of the mountains and strongholds, they came to the plains of Cilicia and imposed their rule as far as the sea-coast. At this time the Byzantine Empire was very weak, and the Mohammedan Seljuks and Arabs were not very strong, as they had become divided among themselves and were engaged in strife with one another. The Crusaders had also formed new Christian principalities in those regions, so that the Rubinians had no fears either of Mohammedans or of any other foe. Precisely one hundred years after the accession of Rubin I., the Armenians possessed the extensive reach of territory between the Taurus Range and the sea, where they had built many fortresses, towns, and even ports. Leo II. (1185) succeeded in repelling the attacks of the Sultan of Damascus and other Mohammedan rulers, even taking some towns from them. During this period, Saladin, Sultan of Egypt, taking advantage of dissension among the crusading princes, attacked them, and took Jerusalem and the rest of Palestine (1187). Then a new Crusade was started, led by the German Emperor Frederick Barbarossa. This monarch sent emissaries to Leo, asking his help against the Mohammedans, promising him a crown as a reward. Leo supplied the Crusaders with provisions and rendered them other assistance. Barbarossa died without fulfilling his promise, but the crown was sent by his successor, Henry VI., after consultation with the Pope of Rome. Leo was crowned king in 1198. The following year, the new Armenian king also obtained recognition from the Byzantine Emperor, who sent him a crown. Leo still further extended his dominions and put the whole kingdom into excellent condition. He did not, like the Bagratunis, re-establish the régime of the Arsacidae, but tried to imitate European institutions, inviting many French, English, and German experts to his kingdom, giving them appointments in the court, the army, and the council. Many new schools were opened in this reign in which the teaching was entrusted to learned Europeans as well as to Armenians. Arts and handicrafts, commerce and agriculture also flourished under this king. Leo died in 1219 after a reign of thirty-four years. For his great services to his people, he was called “Leo the Benefactor.”